Improvement in percussion-fuse for explosive shells



. R. P. PARROTT.

Shell-Fuse;

Patented Mar. 15, 1864.

gvg

III

N-FETERS. FHOTO LITMOGRAPHER WASHINGTON. D C.

UNITED Smarts PATENT @rri'cn,

ROBERT P. PARROTT, OF GOLD SPRING NEXV YORK.

IMPROVEMENT IN PERCUSSlON FUSE FOR EXPLOSll/E SHELLS.

Specification forming part of Letters Patent No.-4lll,937, dated March 15, 1864.

To all whom it may concern:

Be it known that I, ROBERT P. PARROTT, of Cold Spring, in the county of Putnam and State of New York, have invented a new and useful Improvement in Percussion-Fuses for Rifle-Shells; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a side view of a fuse constructed according to my invention Fig. 2 is a central longitudinal section of the same. Fig. 8 is a side view of the cover. Fig. 4 is an inner face view of the same. Fig. 5 is a side view of the plunger capped ready for use. Fig. 6 is a front end view of the same.

Similar letters of reference indicate corresponding parts in the several figures.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A is the hollow plug, made of zinc or other metal, with a screw-thread on its exterior to screw into the fuse-hole of the shell, and'with holes or notches a a in a flange, 1), provided around its outer end for the reception of a screw-driver, by which to screw it into the fuse-hole. This plug is bored or cored centrally and cylindrically for the reception of the plunger 13, the back part of the bore being made smaller than the front part to form a shoulder, c, for the plunger to rest against.

0 is the cover, having a screw-thread on its exterior to fit a screw-thread in the interior of the front end of the plug, and having holes or notches d d in its outer face for the reception of a screw-driver, by which to screw it into the plug, and recesses c c in its inner face for the reception of the ends of the two columns or prongs f f, provided on the front end of the plunger.

The plunger B may be made of the same metal as the plug, of a size to fit easily to the bore of the latter, and with a shoulder, g, corresponding with the shoulder c. The columns or prongs f f, which are provided on its front end, are parallel with its length and as far from its centeras is permitted by its diameter. The said columns or prongs may be from five-eighths to three-quarters of an inch in length, and of such thickness as to resist any concussion in a longitudinal direction to which they may be subject by the dropping of the shell or by other accident, but to bend or twist off easily in a lateral direction, and the whole length of the plunger, from the shoulder 9 to the ends of the prongs, is such that the prongs may be received loosely in the recesses e e, and the shoulder-g fit loosely to the shoulder 0 without binding when the cover 0 is screwed into its place in the plug. The plun ger is made hollow, and a nipple, z, is screwed into the front end of its central cavity, K, for the reception of a percussion-cap, j. The back portion of the central cavity, K, should be filled with gunpowder to carry the fire from the cap j to the charge of the shell, and plugged at its inner end to confine the powder in place. The plunger and cap are inserted in the plug, while the whole are in an inverted position, and in this way the prongs are kept in the recesses in the cover. After the plunger and cover have been secured in the plug and the latter has been inserted in the shell, the plunger, though remaining loose in the plug, is prevented from being accidentally moved lengthwise to any extent by its prongs, which serve as guards to prevent the cap j from striking against the cap 0; but on the discharge of the shell from a rifled cannon the shell will move forward with a velocity of, say, twelve hundred feet per second at the mouth of the cannon, and by taking in the grooves it will acquire a rotary motion proportioned to this velocity and the degree of twist. The twist in a thirty pounder is generally one turn in twelve feet, giving one hundred revolutions per second. Now, it will be seen that the only way by which this rapidity of rotation can be communicated to the plunger is by the prongs, which, in the eifort to overcome the inertia of the plunger, are twisted off or bent over sidewise, and in this way present little or no resistance to the momentum and impact of the plunger when the shell strikes the obstacle against which it is desired to explode. Thus it will be seen that I keep the guard so long as one is wanted, and remove it on the firing of the gun by employing the rotation of the shell itself for the purpose.

It maybe readily understood that the percussion-cap, or other fulminate primary, or the prongs ff might be attached to the cover or head of the plug instead of to the plunger, and be made to operate in the same manner.

2 use"? \VhatI claim as my invention, and desire to secure by Letters Patent, is

The construction and arrangement of the columns or arms f, substantially in the manner herein shown and described, so that said arms will be longitudinally strong, but laterally weak, and thus, when rapid rotation is imparted to the shell by discharge from the gun the arms will bend or break, but at all other times will remain firm and rigid, as set 

